VARIOLITIC DIABASE OF THE FICHTELGEBIRGE. 51 



along the footpath to Heinersreuth the sedimentary rocks may be 

 seen in situ. Hence the diabase was probably close in contact with 

 a band of Devonian, which now crosses the stream obliquely at this 

 point ; so, though the variolitic spheroids are in one place no less 

 than sixty yards from the Devonian horizontally, they may have been 

 nearer to it vertically. 



The gully up which the path rises from the bridge, the river, 

 and a pine-covpred slope completely obscure the junction of this 

 mass of spheroidal diabase with the adjacent beds ; hence one turns 

 to the neighbouring Devonians to follow the margin of their outcrop 

 in the hope of finding a section elsewhere. 



The pathway that goes east to Heinersreuth is at first bounded 

 to the south by steep crags of diabase, while to the north there is a 

 more gentle fir-covered slope in which occasional exposures of the 

 same amygdaloidal diabase are to be seen. The south margin of 

 the Devonian crosses the brook that drains the valley and winds up 

 the slope of the Badleite, at first roughly skirting the wood ; after 

 one or two sharp bends, it turns abruptly to the south, and the 

 Devonians are soon succeeded by the Silurians and Cambrians which 

 rise from beneath them and abut against the diabase. There are 

 no clear sections of the junction, but in a few places the diabase 

 close by it can be seen ; in such cases it is somewhat variolitic, 

 though in places the amygdules that also occur obscure the varioles. 

 Returning to the north side of the valley, an outcrop of Devonian in 

 the bed of the stream enables one to get better acquainted with one 

 important member of this formation — a coarse grit composed of 

 fragments of quartz, quartz-mosaic, micropegmatite, and worn 

 cleavage fragments of plagioclase ; by the increase in the amount of 

 the fine matrix that frequently occurs between the grains, and the 

 decrease in the size of the coarser constituents, the rock passes into 

 a shale ; it is comparatively unaltered, except for a tendency to 

 cleavage. 



Along the north slope of the valley the junction of the diabase 

 and Devonian is buried in fir-woods : occasionally there is a limited 

 outcrop of an amygdaloidal diabase overlain by a thin-bedded shale. 

 The sections are, however, rather unsatisfactory. A little less than 

 a kilometre along the valley the Devonians project into the diabase 

 and run up the slope to the summit of the lliihlleite ; they occupy 

 a slight depression, which at the south end is 100 yards wide. 

 Patches of variolitic diabase occur along the junction, and weathered 

 lumps of it are common upon the surface at the foot of the bank of 

 diabase that bounds the Devonian. The variolite is best seen, 

 in situ, in a tree-covered ridge that forms the eastern boundary of 

 the field occupied by the Devonian shales ; a larger section is 

 exposed in a knoll at the end of this ridge, which overhangs the 

 path to Heinersreuth, The section is as follows, in descending 

 order : — 



1. Massive-jointed and bedded grit (dip 30° to J^., 25° W., mag- 

 netic), 15 feet. 



e2 



